Young Innovators Improve Solar Methods to Purify Water

January 17, 2011

One student innovator in New South Wales and a four-person team of innovators in the state of Washington have developed impressively simple methods for purifying water by using the sun. The information comes from a report at GizMag.

In 2009, student designer Jason Lam from the University of New South Wales developed Solaqua , a water disinfection unit meant to be used in rural sub-Saharan Africa.

The device (pictured left) utilizes ultra-violet and infrared rays from the sun to eliminate pathogens within contaminated water. Raw water is first passed through a sari cloth filter to improve efficiency of solar water disinfection (SODIS). A five tap funnel fills five specially designed bottles to obtain ten liters of water. By spreading and laying the bottles on the ground, the transparent bottle surface allows maximum exposure to UV rays. The black, back surface of each bottle absorbs heat, while reflective inner surfaces reflect UV rays within the water itself.

According to Lam, “Water purification, filtering and, or disinfection is an important aspect in the lives of many people living in rural sub-Saharan Africa. Diarrheal diseases claim the lives of many, especially children under five.”

SODIS is a low-cost method for disinfecting water, by exposing water in closed plastic bottles to direct sunlight. Unfortunately, there has been no reliable way of knowing when bottled water has reached a safe level of purity. That is, until four engineering students from the University of Washington developed a simple, inexpensive device for measuring purity. As a result, the student team won US$40,000 in the process.

According to GizMag, the UW students took part in a contest promoted by InnoCentive Inc., a website where organizations post technical challenges and invite solutions. In this case, the nonprofit GlobalGiving Foundation had asked other nonprofits around the world to submit their water-related challenges, from which it chose five to post on InnoCentive.

The students, Chin Jung Cheng, Charlie Matlack, Penny Huang and Jacqueline Linnes, developed a device using parts from a keychain that blink when exposed to light. When attached to a water bottle, it monitors how much light passes through the water. An indicator light blinks on and off as long as particulates obstruct the light flow, then stops blinking once the water is safe to drink.

The student team estimates that parts for each device would cost about US$3.40. Matlack says the device contains “all the same components that you’d find inside a dirt-cheap solar calculator, except programmed differently.”

Writer, documentary producer, and director. Meyers is a contributor to CleanTechnica, and founder of Green Streets MediaTrain, a communications connection and eLearning hub. As an independent producer, he's been involved in the development, production and distribution of television and distance learning programs for both the education industry and corporate sector. He also is an avid gardener and loves sustainable innovation.